Uploaded Attachment from AmazonSimpleEmailServiceV2 was not valid

[berviantoleo]

Describe the bug

I downloaded the file from S3 and sent the downloaded file as a stream to the AmazonSimpleEmailServiceV2.

I identified that the downloaded size is correct (same as the S3 object size). But the received file size (the attachment) was wrong (doubled). Which causes the invalid attached file.

I tried to ensure the MemoryStream is valid. But, seems when encoding to base64.

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

The attachment file is correct.

Current Behavior

The attachment file size is doubled and invalid.

Reproduction Steps

1. Download a file from S3 and create a copy stream.
2. Send the attachment (ensure the attachment is more than 10 MB and under 40 MB) using AmazonSimpleEmailServiceV2.SendEmail using the copied stream.

Possible Solution

No response

Additional Information/Context

• Affected codes

• Simple Example - https://gist.github.com/berviantoleo/e0cda6eb7020c90532a81967ba0cb546

• Another sample - https://gist.github.com/berviantoleo/82b5f606eefe74194496f5f4f3367733

AWS .NET SDK and/or Package version used

AWSSDK.SimpleEmailV2 4.0.0.2
AWSSDK.S3 4.0.0.2

Targeted .NET Platform

.NET 8

Operating System and version

Amazon Lambda

[dscpinheiro]

The base64 encoding of MemoryStreams is intentional (not only for SES but all JSON based services). But the SDK will not modify the content sent to the API (the service client is 100% generated).

Do you have a shorter reproduction code? The code you linked has extra logic that I think could make our investigation harder (e.g. compressing the downloaded file).

[berviantoleo]

How about using the previous commit?

bervProject/MergePDFOnline@64a11d9

https://github.com/bervProject/MergePDFOnline/blob/64a11d90389f0c534a41f0efad0f3c310d0790d2/BervProject.MergePDF.Lambda/src/BervProject.MergePDF.Lambda/Functions.cs

It's not using compression.

If not the case, I'll try using another simple code.

[dscpinheiro]

Yeah, a simple example (like the https://sscce.org/ mentioned in our issue template) would be helpful.

[berviantoleo]

I created a simple example using a Console app.

• With downloading file
  https://gist.github.com/berviantoleo/e0cda6eb7020c90532a81967ba0cb546

• Without downloading file (ensure the file is more than 10 MB)
  https://gist.github.com/berviantoleo/82b5f606eefe74194496f5f4f3367733

[ashishdhingra]

The issue is reproducible using the provided code in last comment. Upload a 22.1MB PDF in S3 and used the provided code to download the file and send the file using SES V2. The sent file was 36.6MB in size. Opening the file didn't display the pages in PDF file.

• EmailContentMarshaller is resolving to Simple email instead if Raw based on customer's code.
  • If we need to send attachments, Raw email format should be used (refer https://repost.aws/questions/QUSF_ZSD1PQwOiURVEyTF_hQ/send-email-with-aattachment-on-aws-ses-in-c-net-using-amazon-simpleemailv2).
• This uses MessageMarshaller, which uses AttachmentMarshaller here to handle attachments.
  • AttachmentMarshaller uses StringUtils.FromMemoryStream() to set the raw content here, which uses Convert.ToBase64String() to write Base64 encoded content. Thereafter, the attachments are handled by SES service.

Needs investigation on how other SDK(s) are handling the above scenario.